ARS | Publication request: Novel antibacterial polypeptide laparaxin produced by Lactobacillus paracasei strain NRRL B-50314 via fermentation

Submitted to: Applied Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 25, 2012
Publication Date: June 14, 2012
Citation: Liu, S., Wilkinson, B.J., Bischoff, K.M., Hughes, S.R., Rich, J.O., Cotta, M.A. 2012. Novel antibacterial polypeptide laparaxin produced by Lactobacillus paracasei strain NRRL B-50314 via fermentation. J Pet Environ Biotechnol. 3:121. DOI: 10.4172/2157-7463.

Interpretive Summary: This study reports the discovery of a novel antibacterial polypeptide designated laparaxin. Because conventional antibiotics are not easily degraded, thus residues can be accumulated in the environment and lead to the emergence of multi-drug resistant strains. New biodegradable bactericidal agents are needed to control and treat infections of multi-drug resistant strains. In the present study, a biodegradable polypeptide laparaxin, produced by Lactobacillus paracasei NRRL B-50314, was found capable of inhibit growth of numerous Gram-positive pathogens. This study will be of interest to researchers attempting to design biodegradable intervention strategies to control bacterial infections. The scale-up production of laparaxin could have potential impact in clinical and veterinary medicine, as well as in controlling contamination in the food and feed industries.

Technical Abstract: This study reports the production and characterization of a novel antibacterial polypeptide, designated laparaxin, which is secreted by Lactobacillus paracasei NRRL B-50314. Crude laparaxin has antibacterial activity against a wide variety of Gram-positive bacteria, including: lactic acid bacteria (Lactococcus lactis and Lactobacillus buchneri), food-borne pathogens (Listeria monocytogenes), gastrointestinal pathogens (Enterococcus faecalis), and opportunistic pathogens (Staphylococcus aureus methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) strains, a hetero-vancomycin-intermediate methicillin resistant strain (HeteroVISA also MRSA) MM66, and homogeneous vancomycin intermediate (Homo VISA). Using L. lactis as an indicator strain, the inhibitory activity of crude laparaxin was detected originally in early log phase, and the activity maximizes at the early stationary phase and remains stable after prolonged incubation. Laparaxin activity is stable after 30 min of incubation at 94oC. Higher concentrations of inhibitory activity are produced when glucose, fructose, and sucrose are used as carbon-sources in growth media. Crude laparaxin has potential applications in food and feed industries, as well as in clinical and veterinary medicine.